JPH05146109A - Magnetic bearing and motor - Google Patents

Abstract

PURPOSE:To obtain a magnetic bearing which can prevent the abrasion of a shaft even if it is simple structured. CONSTITUTION:A shaft 2 is provided with a first inner magnetic member 16 constituted of a plate member 12 and a magnet plate 14 and a second inner magnetic member 22 constituted of a plate member 18 and a magnet plate 20. Around the shaft 2, a first outer magnetic member 28 is so secured as to face the first inner magnetic member 16 and a second outer magnetic member 30 is so secured as to face the second inner magnetic member 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a shaft (rotating shaft).
The present invention relates to a magnetic bearing for rotatably supporting a magnetic field using a magnetic force and a motor using the magnetic bearing.

[0002]

2. Description of the Related Art A sliding bearing and a rolling bearing are widely used as a bearing for supporting the rotational movement of a shaft. Shaft wear is inevitable.

To prevent this, an electromagnet provided around the shaft and driven by a control circuit,
There is a magnetic bearing equipped with a sensor for detecting the displacement of the shaft in the thrust direction and the radial direction. However, in such a magnetic bearing, a control circuit for driving and controlling an electromagnet is essential, and the entire device has a complicated configuration. There was a drawback that became.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic bearing capable of preventing wear of a shaft with a simple structure.

[0005]

A magnetic bearing according to the present invention is a magnetic bearing that rotatably supports a shaft by using a magnetic force. (A) An outer peripheral portion extends from one end to the other end in the axial direction. A first inner magnet member that is gradually expanded in diameter as it goes, a magnetized portion having the same polarity is formed in at least the outer peripheral portion over the entire circumferential direction, and the inner peripheral portion is attached to the shaft; B) The outer peripheral portion is gradually expanded in diameter from one end in the axial direction toward the other end, and at least the outer peripheral portion is formed with a magnetized portion having the same polarity over the entire circumferential direction, and the inner peripheral portion is A second inner magnet member mounted on the shaft in a state where one end or the other end in the axial direction of the first inner magnet member is opposed to each other, and (C) an inner peripheral portion is formed from one end in the axial direction. Increasing the diameter gradually toward the other end A magnetized portion having the same polarity as the outer peripheral portion of the first inner magnet member is formed at least in the inner peripheral portion over the entire circumferential direction. A first outer magnetic member that is fixedly arranged so as to face the outer peripheral portion of the magnetic member and is spaced apart by a fixed distance;
The inner peripheral portion is gradually expanded in diameter from one end to the other end in the axial direction, and at least the inner peripheral portion has the same polarity as the outer peripheral portion of the second inner magnetic member over the entire circumferential direction. And a second outer magnet member fixedly arranged with the inner peripheral portion facing the outer peripheral portion of the first inner magnet member and being separated by a fixed distance. It is a feature.

The first inner magnet member and the second inner magnet member may be integrally molded, and the first inner magnet member may be formed integrally.
The outer magnetic member and the second outer magnetic member may be integrally formed. Further, the first inner magnet member and the second inner magnet member may be integrally molded, and the first outer magnet member and the second outer magnet member may be integrally molded. ..

Further, a motor according to the present invention uses the magnetic bearing, and in the magnetic bearing, the first inner magnet member and the second inner magnet member of the shaft are used.
The rotor is mounted between the inner magnetic member and the inner magnetic member, and the stator is fixedly arranged around the rotor.

[0008]

In the magnetic bearing having the above structure, the directions of repulsion between the first inner magnet member and the first outer magnet member and between the second inner magnet member and the second outer magnet member The magnetic force of (repulsive magnetic force) acts. The radial component of the repulsive force suppresses the radial movement of the shaft within a certain range. Further, the thrust direction component of the repulsive magnetic force acting between the first inner magnetic member and the first outer magnetic member, and the thrust direction component of the repulsive magnetic force acting between the second inner magnetic member and the second outer magnetic member. Since this component is in the opposite direction to that of the component, the balance suppresses the movement of the shaft in the thrust direction within a certain range.

Further, in the motor using the magnetic bearing, the shaft is rotationally driven by the magnetic bearing without loss due to friction.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, 2 is a shaft. Disc-shaped projecting portions 4 and 6 are formed at two locations on the shaft 2, and screw portions 8 and 10 are formed at portions connecting to the projecting portions 4 and 6.
Are formed.

The screw portion 8 is formed in a substantially disc shape,
A plate member 12 having a female screw portion formed on the inner peripheral portion is screwed, and a magnet plate 14 made of a ferromagnetic material is fixed to the lower side of the plate member 12 in FIG. The plate member 12 and the magnet plate 14 form a first inner magnet member 16.

The outer peripheral portion 14a of the magnet plate 14 is formed in a conical shape whose diameter increases toward the upper side in the axial direction of the shaft 2, and the outer peripheral portion of the magnet plate 14 (corresponding to the magnetized portion).
Is magnetized to the N pole, and the inner peripheral side portion is magnetized to the S pole.

A plate member 18 having a female screw portion formed on the inner peripheral portion, which is substantially the same in shape as the plate member 12, is screwed into the screw portion 10. The upper side of the plate member 18 is made of a ferromagnetic material. The magnet plate 20 is fixed. Plate member 18 and magnet plate 2
0 constitutes the second inner magnet member 22.

An outer peripheral portion 20a of the magnet plate 20 is formed in the same shape as the magnet plate 14, that is, a conical shape whose diameter is expanded downward in the axial direction of the shaft 2.
The outer peripheral side portion (corresponding to the magnetized portion) is magnetized to the S pole, and the inner peripheral side portion is magnetized to the N pole.

A cylindrical member 2 is provided on the outer peripheral portion of the shaft 2.
4 are fixedly arranged, and a cylindrical spacer 26 is arranged inside the cylindrical member 24. The ring member 2 made of a ferromagnetic material is provided on the upper end side and the lower end side of the cylindrical member 24.
The ring members 28 and 30 are fixed to each other.
Caps 32 and 34 are attached and fixed so as to cover the outside of the end of the cylindrical member 24 (corresponding to the first outer magnetic member), 30 (corresponding to the second outer magnetic member), and the cylindrical member 24.

The inner peripheral portion 28a of the ring member 28 is formed in a conical shape whose diameter gradually increases toward the lower side in the axial direction of the shaft 2, and is opposed to the outer peripheral portion of the magnet plate 14 for a certain distance. It is in a separated state. Further, the inner peripheral side portion of the ring member 28 (corresponding to the magnetized portion) is N
The pole and the outer peripheral side portion are magnetized to the S pole, respectively.

The ring member 30 has the same shape as the ring member 28, and the inner peripheral portion 30a thereof is formed in a conical shape whose diameter gradually increases toward the lower side in the axial direction of the shaft 2 and the outer peripheral portion of the magnet plate 20. And are separated from each other by a certain distance. The inner peripheral side portion (corresponding to the magnetized portion) of the ring member 30 is magnetized to the S pole, and the outer peripheral side portion is magnetized to the N pole.

In the magnetic bearing having the above structure, the outer peripheral portion 14a of the magnet plate 14 and the inner peripheral portion 28a of the ring member 28 arranged so as to face the outer peripheral portion 14a have the same polarity (N pole). Therefore, a magnetic force (repulsive magnetic force) in a repulsive direction acts on each other. Similarly, since the outer peripheral portion 20a of the magnet plate 20 and the inner peripheral portion 30a of the ring member 30 arranged so as to face the outer peripheral portion 20a have the same polarity (S pole), the magnet plate 20 and the ring. The repulsive magnetic force also acts on the member 30.

The radial component of the repulsive force suppresses the radial movement of the shaft 2 within a certain range.

The thrust-direction component of the repulsive magnetic force acting between the magnet plate 14 and the ring member 28 and the thrust-direction component of the repulsive magnetic force acting between the magnet plate 20 and the ring member 30 are opposite to each other. Because of the balance, the balance suppresses the movement of the shaft 2 in the thrust direction within a certain range.

Further, in this embodiment, the plate member 12,
By adjusting the amount of screwing 18 onto the shaft 2, the clearances between the magnet plate 14 and the ring member 28 and between the magnet plate 20 and the ring member 30 can be adjusted.

The first inner magnet member, the second inner magnet member,
The shapes of the first outer magnetic member and the second outer magnetic member are not limited to those in the above-described embodiment, and may be, for example, as shown in FIG.

This figure shows the magnetic bearing of FIG.
Magnet plates 36 and 40 are provided instead of the magnet plates 14 and 20, respectively, and the ring member 4 is replaced with the ring members 4 and 30.
The first inner magnet member 38 is composed of the plate member 12 and the magnet plate 36, and the second inner magnet member 42 is composed of the plate member 18 and the magnet plate 40. It Outer peripheral portion 36a of magnet plate 36, outer peripheral portion 4 of magnet plate 40
0a, the inner peripheral portion 44a of the ring member 44 and the ring member 4
The inclination of the inner peripheral portion 46a of No. 6 with respect to the shaft 2 is as shown in FIG.
The outer peripheral portion 14a of the magnet plate 14, the outer peripheral portion 20a of the magnet plate 20, the inner peripheral portion 28a of the ring member 28, and the inner peripheral portion 30a of the ring member 30 in FIG. It has the same structure as the No. 1 magnetic bearing.

Even with such a structure, the magnet plate 3
6, the thrust-direction component of the repulsive magnetic force acting between the magnet 6 and the ring member 44 and the thrust-direction component of the repulsive magnetic force acting between the magnet plate 40 and the ring member 46 are in diametrically opposite directions. As with the bearing, the movement of the shaft 2 in the thrust direction can be suppressed within a certain range.

The shapes of the outer peripheral portions of the first inner magnetic member and the second inner magnetic member, and the inner peripheral portions of the first outer magnetic member and the second outer magnetic member are the above-mentioned conical shapes. However, the shape is not limited to, and may be, for example, a spherical shape or a paraboloidal shape.

Further, the first inner magnet member and the second inner magnet member may be integrally formed, or the first outer magnet member and the second outer magnet member may be integrally formed, Both may be integrally formed as shown in FIG.

In FIG. 3, a magnet plate 52 corresponding to a first inner magnet member and a magnet plate 50 corresponding to a second inner magnet member are integrally molded, and a magnet plate 52 is attached to the shaft 2. Around the plate 52, the ring member 5 corresponding to the first outer magnet member.
4 and a ring member 56 corresponding to the second outer magnet member are integrally molded, and a ring member 58 is fixedly arranged. With such a structure, the length of the magnetic bearing in the axial direction is shortened and the magnetic bearing is made compact.

According to the magnetic bearing shown in each of the above-mentioned embodiments, the load in the radial direction and the thrust direction of the shaft 2 can be applied with a simple structure without requiring a complicated control circuit and the like unlike the conventional magnetic bearing. Shaft 2 while receiving
Can be rotatably supported. Therefore, not only is the manufacturing cost superior to the conventional magnetic bearing, but also energy saving is superior because energy is not required for use. Further, unlike the conventional magnetic bearing, the control circuit, the sensor, and the like do not break down, so that it is also excellent in safety with an emphasis on stability.

The above magnetic bearing is applied to a motor, a rotor is mounted between the first inner magnet member and the second inner magnet member of the shaft, and the stator is fixedly arranged around this rotor. A motor having the configuration described above is obtained.

FIG. 4 shows a stepping motor constructed by using the magnetic bearing shown in FIG. 1, which is a cylinder in which a magnetized portion having multiple poles is formed in the circumferential direction between the magnet plates 14 and 20 of the shaft 2. -Shaped rotor magnet 60 is mounted, a stator 62 is disposed inside the spacer 26 so as to cover the rotor magnet 60, and a coil 64,
66 is provided.

As described above, in the motor using the magnetic bearing described above, the shaft 2 is rotatably driven by the magnetic bearing without loss due to friction, so that the driving efficiency is higher than that of the motor using the conventional ball bearing. Can be significantly improved.

[0032]

As described above, according to the magnetic bearing of the present invention, the first inner magnet member, the second inner magnet member,
It has a simple structure in which only the first outer magnet member and the second outer magnet member are provided, and does not require a control circuit or the like, and rotatably supports the shaft while receiving the load in the radial direction and the thrust direction of the shaft. be able to. Therefore, in addition to being superior in manufacturing cost compared to conventional magnetic bearings,
It is also excellent in energy saving, and further, it is excellent in terms of safety with an emphasis on stability, since it does not damage the control circuit, the sensor and the like.

Further, according to the motor of the present invention, the shaft is rotationally driven by the magnetic bearing without loss due to friction, so that the driving efficiency is remarkably improved.

[Brief description of drawings]

FIG. 1 is a magnetic bearing according to an embodiment of the present invention.

FIG. 2 is a magnetic bearing according to another embodiment of the present invention.

FIG. 3 is a magnetic bearing according to another embodiment of the present invention.

FIG. 4 is a motor according to another embodiment of the present invention.

[Explanation of symbols]

 2 shaft 16 1st inner magnet member 22 2nd inner magnet member 28 1st outer magnet member 30 2nd outer magnet member 38 1st inner magnet member 42 2nd inner magnet member 44 1st outer magnet Member 46 Second outer magnet member 48 First inner magnet member 50 Second inner magnet member 54 First outer magnet member 56 Second outer magnet member 60 Rotor 62 Stator

Claims (5)

[Claims] 1. A magnetic bearing for rotatably supporting a shaft using a magnetic force, wherein (A) an outer peripheral portion is gradually expanded in diameter from one end to the other end in the axial direction, and at least the outer peripheral portion. Is formed with a magnetized portion having the same polarity over the entire circumferential direction, and a first inner magnetic member having an inner peripheral portion attached to the shaft, and (B) an outer peripheral portion from one end in the axial direction to the other. The diameter is gradually increased toward the end, and a magnetized portion having the same polarity is formed at least in the outer peripheral portion over the entire circumferential direction, and the inner peripheral portion is used as the shaft, the first inner magnetic member and the axis line. A second inner magnet member to be mounted in a state where one end in the direction or the other end face each other, and (C) the inner peripheral portion is gradually expanded in diameter from one end in the axial direction toward the other end, and at least The inner circumference is the entire circumference Over magnetized with the same polarity and the outer peripheral portion of said first inner magnetic member and is formed, the inner circumferential portion, said first
A first outer magnetic member that is fixedly arranged so as to face the outer peripheral portion of the inner magnetic member and is spaced apart by a certain distance; and (D) the inner peripheral portion gradually expands from one end to the other end in the axial direction. A magnetized portion having a same polarity as that of the outer peripheral portion of the second inner magnetic member is formed over at least the inner peripheral portion in the entire circumferential direction, and the inner peripheral portion is provided with the first magnetized portion.
And a second outer magnet member that is fixedly arranged so as to face the outer peripheral portion of the inner magnet member and is separated by a fixed distance. 2. The magnetic bearing according to claim 1, wherein the first inner magnet member and the second inner magnet member are integrally formed. 3. The magnetic bearing according to claim 1, wherein the first outer magnetic member and the second outer magnetic member are integrally molded. 4. The first inner magnet member and the second inner magnet member are integrally molded, and the first outer magnet member and the second outer magnet member are integrally molded. The magnetic bearing according to claim 1, which is characterized in that. 5. The magnetic bearing according to claim 1, wherein
A motor, wherein a rotor is mounted between the first inner magnet member and the second inner magnet member of the shaft, and a stator is fixedly arranged around the rotor.